This patent specification relates to medical ultrasound imaging systems. In particular, it relates to an easy-to-use user interface that promotes consistent and reliable recordation of probe position during a breast ultrasound scan.
Ultrasound imaging systems have become increasingly popular for use in medical diagnosis because they are non-invasive, easy to use, capable of real-time operation, and do not subject patients to the dangers of electromagnetic radiation. Instead of electromagnetic radiation, an ultrasound imaging system transmits sound waves of very high frequency (e.g., 1 MHz to 15 MHz) into the patient and processes echoes scattered from structures in the patient""s body to derive and display information relating to these structures.
Ultrasound imaging systems have been increasingly used in breast cancer screening, detection, treatment, and research. Most commonly, a breast ultrasound procedure involves the placement of an ultrasound probe over a region of interest of the breast, with the radiologist or other medical professional (hereinafter xe2x80x9cuserxe2x80x9d) simultaneously viewing a real-time ultrasound image output on a computer monitor. The monitor also usually displays relevant text and/or graphical information near the ultrasound image for simultaneous viewing by the user. The user then presses a button to freeze the display, at which time the display may be printed on a printer or stored in digital format for later viewing and analysis.
Because much downstream analysis, interpretation, and decisionmaking may be performed based on the printed or stored information, it is crucial to ensure that the text annotation and/or graphical information relevant to the ultrasound image be both correct and properly formatted. As PACS (picture archiving and communication systems) and teleradiology (i.e., the calling up of archived images from remote locations by telephone line or internet connection) continue to increase in importance, the accurate and consistent annotation of ultrasound and other medical images will become increasingly important. Additionally, it is expected that accurate and consistent annotation of ultrasound and other medical images will become increasingly important as historical archives of breast ultrasounds and other medical images are built up over time for statistical analysis or other research purposes.
FIG. 1 shows a conventional ultrasound display 100 comprising an ultrasound image 102, a body marker region 104, other ultrasound parameters 106, and a user-typed text string 108. Body marker region 104 has the important purpose of illustrating to a subsequent viewer the position of the ultrasound probe when the ultrasound image 102 was taken. Body marker region 104 comprises left and right breast icons 110 and 112, respectively, against which a movable probe icon 114 is manipulated by the user to reflect the current position of the ultrasound probe. Most commonly, a trackball input is used to manipulate the location of probe icon 114 relative to the breast icons, while a probe orientation knob is rotated to manipulate the orientation of the probe icon 114 relative to the breast icons. Other ultrasound parameters 106 is a text display of relevant parameters such as time, date, probe power, frame rate, etc.
User-typed text string 108, shown in FIG. 1 by the characters xe2x80x9cph lesionxe2x80x9d (representing the term xe2x80x9cphantom lesionxe2x80x9d), is input by the user by positioning a freely movable text cursor, using a trackball, to the relevant location on the ultrasound output 100 and then entering the relevant text portion. This is usually done to point out certain aspects of the ultrasound image 102 that may be interesting to a subsequent viewer but that may, or may not, be immediately apparent to the subsequent viewer.
Finally, ultrasound display 100 comprises a probe position text sequence 116 placed within the body marker region 104. In conventional systems, the probe position text sequence 116 is typed in by the user, using the same or similar text input mode that is used to enter the user-typed text string 108. The probe position text sequence 116 is shown in FIG. 1 as having been only partially input, with a cursor moving to the right as it is typed in by the user. The probe position text sequence 116 is intended to textually communicate the position of the ultrasound probe as graphically expressed by the location and orientation of the probe icon 114. As used herein, the term xe2x80x9clocationxe2x80x9d refers to the x-y placement of the ultrasound probe/probe icon (and also the z coordinate if applicable). The term xe2x80x9corientationxe2x80x9d refers to the direction in which probe icon/ultrasound probe transducer array is pointed. The term xe2x80x9cpositionxe2x80x9d refers to the collective location and orientation information.
As known in the art, typical examples of probe position text sequence 116 may include: (i) xe2x80x9cLeft BR, Antiradial, 1:30, 3 cm,xe2x80x9d meaning that the probe is over the left breast, is at a radius of 3 cm from the left nipple at an angle of 1:30 (i.e., 45 degrees from vertical using clock coordinates), and has an orientation in the antiradial direction (i.e., is tangent to a circle centered on the left nipple at the 1:30 location); (ii) xe2x80x9cLeft BR, Radial, 6:00, 5 cm,xe2x80x9d meaning that the probe is located over the left breast 5 cm directly below the left nipple and is oriented in the radial direction, (iii), xe2x80x9cRight BR, Trans, 10:00, 4 cm,xe2x80x9d meaning that the probe is located over the right breast at 4 cm in the 10:00 direction from the right nipple and is oriented in the transverse direction (i.e., parallel to a line between the two breast nipples), (iv) xe2x80x9cRight BR, Long, 7:00, 8 cm,xe2x80x9d meaning that the probe is over the right breast at 8 cm in the 7:00 direction and is oriented in the longitudinal direction (i.e., parallel to the longitudinal or sagittal axis of the body), and (v) xe2x80x9cLeft BR, Oblique, 8:00, 3 cmxe2x80x9d meaning that the probe is over the left breast at 3 cm in the 3:00 direction, and is not oriented along any standard direction. As known in the art, examples (i) and (ii) above express the orientation of the probe with respect to a radial/antiradial coordinate system, while examples (iii) and (iv) express the orientation of the probe with respect to a transverse/longitudinal coordinate system. In general, the xe2x80x9cobliquexe2x80x9d designation in example (v) may be used with either the radial/antiradial or transverse/longitudinal coordinate system.
One problem that arises with the system of FIG. 1 is that the user is required to alphanumerically key in the probe position text sequence 116 when such text is desired. This process can be cumbersome, can lead to user frustration, and, when many breast ultrasound scans are being recorded, can lead to user fatigue. Sonographers must routinely manipulate the ultrasound probe with one hand and operate the ultrasound system controls and keyboard with the other. The hand that manipulates the probe is often times gloved and/or encumbered by having ultrasound gel on it. With interventional procedures including biopsies and ductography, contamination may occur from blood and/or nipple discharge as well. Conventional annotation mechanics that require any keyboard entries mean that the operator either has to stop, wipe their hands, and then type with both hands, or, use a keyboard designed for two hands with a single hand. Further, unless the operator truly goes to the sink and washes thoroughly and carefully before typing on the keyboard, there is the potential for contamination of the keyboard with pathogens such as fomites. These could be passed on to later patients by the operator. Also, there is the potential for damage of the equipment by moisture from the ultrasound gel deposited on the keyboard and controls.
Moreover, any delays incurred while typing in the probe position text sequence 116 can lead to the possibility that the ultrasound probe may have moved slightly in the meantime. Due to frustration, fatigue, or other factors, the user may return to properly adjust the probe icon 114 and the probe position text sequence 116. This can result in decreased correlation between the ultrasound image and the supporting information the printed or digitally stored copy.
Another disadvantage of the system of FIG. 1 is that different users may incorporate different text schemes for entering the probe position text sequence 116, or the same user may use different text schemes at different times. As a result, different ultrasound output pages from the same laboratory or even the same user may differ in the format of their probe position text sequences. Especially in environments in which such information would be digitally stored, this is disadvantageous because it makes statistics gathering or other off-line automated analysis difficult to achieve across large volumes of ultrasound outputs. Given the potential future usefulness of such information in tracking historical data associated with different patients or populations, it may be important to ensure uniformity in the probe position text sequences of ultrasound output pages.
Finally, another disadvantage of the system of FIG. 1 is that even the purely graphical manipulation of the probe icon 114 may be cumbersome if the user wished the ultrasound probe position to remain in a major direction. For example, if the user is recording two successive ultrasound frames in the antiradial orientation at two different locations, then after the first frame the user must move the trackball until the probe icon is at the second location, and then must carefully re-manipulate the probe orientation knob until the probe icon is oriented in the antiradial direction. This process is unnecessarily cumbersome when it is already known that the probe icon should be in the antiradial direction at the second location.
While a completely automatic position sensing system might represent one option for providing an automatic recording of probe position information, including text-based information, it has been found that position sensing equipment can be cumbersome to use in clinical applications. Moreover, the accuracy of such systems can be reduced because the patient""s breast nipples, used as reference points in the probe position display, often move around during the ultrasound procedure. This reduces the usefulness of the position sensor readouts as replacements for the medical professional""s own estimation of probe position.
Accordingly, it would be desirable to provide an ultrasound system that is easier to use in terms of the textual recordation of user estimates of ultrasound probe position.
It would be further desirable to provide an ultrasound system that is easier to use in terms of orientating a probe icon along major directions while manipulating the probe icon.
It would be still further desirable to provide an ultrasound system that promotes uniformity in the formatting of probe position text sequence outputs.
It would be even further desirable to provide an ultrasound system for which the user can functionally operate the controls efficiently and ergonomically with one hand.
In accordance with a preferred embodiment, a method and system for providing ultrasound probe position information corresponding to an ultrasound image of a target are provided, wherein a text sequence corresponding to a user""s estimate of the position of an ultrasound probe is automatically generated based on the user""s graphical manipulations of a probe icon relative to a breast icon. User inputs are received through a trackball, knob, mouse, or other graphical input device and used to adjust the position of the probe icon relative to the breast icon. The probe position text sequence is automatically generated and continuously updated as the probe icon is manipulated. Because the user is no longer required to manually key in their estimate of the probe position, they may concentrate more easily on accurate placement of the probe icon on the ultrasound display. Moreover, user fatigue associated with repeated keypad entries is avoided. Additionally, probe position text sequences are generated in a common format without unnecessary truncations or misspellings, thereby being more amenable to digital archiving and subsequent computerized access and analysis.
In one preferred embodiment, the user is permitted to select a snapping mode of operation in which the probe icon is snapped to align with a major direction of a preselected coordinate system. In one particular preferred embodiment, this snapping mode is automatically associated with the user""s selection of a radial/antiradial coordinate system, for which this snapping mode has been found to be particularly useful and convenient. If the preselected coordinate system is the transverse/longitudinal coordinate system, this snapping mode is not automatically activated, for permitting a large range of oblique orientations to be recorded.
In another preferred embodiment, the user is permitted to select a classification mode of operation in which the location of the probe icon is automatically classified into one of a plurality of standardized zones based on its position with respect to a reference point, such as a nipple of the patient""s breast. A text representation of this zone is included in the probe position text sequence. Optionally, the user is permitted to select a manual override mode of operation in which the probe position text sequence may be altered or appended by the user.